Impacts of an Invasive Snail on Native Invertebrate Biomass Trista E. Niekum, Erin R. Hotchkiss, and Dr. Robert O. Hall

Invasive Species Not native to the ecosystem Invasive species can alter the abundance and distribution of native species (Simon and Townsend 2003) Example: Zebra Mussels in the United States Wikipedia

What we don’t know Long-term effects on native species Hard to compare pre- and post-invasion Most studies are not ecosystem wide

Kelly Warm Springs Located in Grand Teton National Park Warm throughout the year (exceeds 30ºC in the summer) The invasive snail showed up between 2001 and 2004 Comparing pre- and post-invasion biomass of the invertebrates in the stream Photos by E. R. Hotchkiss

Melanoides tuberculata Malaysian Trumpet Snail Big in the aquarium trade Population has increased drastically since being introduced 80% of the invertebrate biomass in 2006 (Hotchkiss and Hall 2010) Photos by E. R. Hotchkiss

Research Question How has the invasive snail impacted the native invertebrate biomass?

Methods Stovepipe sampler 15.2 cm in diameter was used to collect benthic invertebrates Each sample was sorted using a 1-mm and 250-µm sieves and preserved in 95% ethanol Each invertebrate was measured to the nearest .5 mm to calculate biomass Photos by E. R. Hotchkiss

Biomass tells more of how much is in the stream than the number of individuals Ash-free Dry Mass (AFDM): Is the amount of organic matter that an individual is composed of.

2001 Native Invertebrates

2006 Invertebrates

Omnivores: feed on animals, detritus, plants, Feeding Habits Omnivores: feed on animals, detritus, plants, and algae Easy to compare because their feeding habits are the same and will be found in the same parts of the stream

Introduction of invasive snail vs. vs. Introduction of invasive snail

vs. + + 3 Native Invertebrates

Melanoides has decreased the native invertebrate biomass From Aug 2001 to Aug 2007 Hyalella azteca decreased by 26.5% Chironomidae decreased by 55.9% Helicopsyche decreased by 67.7%

Fishes in Kelly Warm Springs Native Fishes Invasive Fishes Utah Chub Redside shiner Speckled dace Longnose dace Green swordtail Madtom Convict cichlid Guppy Photos by Chad Whaley

How has Melanoides affected the foodweb? ? ? ? ? Native Invertebrate Biomass Native Invertebrates Primary Producers (Plants and algae) Melanoides tuberculata (80% of total invertebrate biomass) Green Swordtail Cichlid Madtom Guppy Speckled Dace Utah Chub Redside Shiner Longnose Dace

Questions?

Work Cited Background Picture: Fore, L. S. and A. Wildrick. 1998. Field Guide to Freshwater Invertebrates. http://www.seanet.com/~leska/Online/petri.gif